JPH085985A - Liquid crystal driving device - Google Patents

Abstract

PURPOSE:To provide the liquid crystal driving device which is small-sized, inexpensive, and small in current consumption and has excellent package efficiency by supplying only the driving voltage that a driving circuit uses from a power circuit in cycles of the AC driving of liquid crystal. CONSTITUTION:The power circuit 11 is equipped with four voltage dividing and selecting circuits 11a-11d, which selectively generate a driving voltage V0 and a driving voltage V1, a driving voltage V4 and a driving voltage V5, a driving voltage V3 and the driving voltage V0, and the driving voltage V5 and a driving voltage V2 according to variation of an AC-converted signal M for the AC driving of LCD between '1' and '0'. The voltage dividing and selecting circuits 11a and 11b supply the generated driving voltage V0 and driving voltage V4 or driving voltage V1 and driving voltage V5 selectively to a common driver 14, and the voltage dividing and selecting circuits 11c and 11d supply the generated driving voltage V3 and driving voltage V5 or driving voltage V0 and driving voltage V3 selectively to a segment driver 15. The common driver 14 and segment driver 15 properly select the two kinds of supplied driving voltages and supply it as a driving signal to the LCD.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal driving device,
More specifically, the present invention relates to a liquid crystal drive device that reduces power consumption and packaging density.

[0002]

2. Description of the Related Art Conventionally, a liquid crystal drive device is generally provided with a liquid crystal display panel (LCD), a drive circuit for driving the liquid crystal display panel, a power supply circuit, a control circuit, etc. Drive voltages having a plurality of voltage values are supplied.

The liquid crystal generally needs to be driven by an alternating current, and the driving circuit is suitable for display from driving voltages of a plurality of voltage values supplied from a power supply circuit and is driven corresponding to an alternating current driving signal. A voltage is selected, a drive signal corresponding to the voltage value of the selected drive voltage is supplied to the LCD, and L
Display drive of CD.

That is, the conventional liquid crystal drive device 1 has a power supply circuit 2 and a common driver 3 as shown in FIG.
And the segment driver 4 and the like. The common driver 3 and the segment driver 4 are mounted by, for example, a PCB board or a TAB method.

The common driver 3 is connected to a common line of an LCD (Liquid Crystal Display) not shown, and the segment driver 2 is connected to a segment line of the LCD.

The power supply circuit 2 includes reference power supplies VEE, VSS (V
EE> VSS) is input, and the power supply circuit 2 includes a plurality of voltage dividing resistors R1, R2, R3, R4, R5 which are interposed between the reference voltage VSS and the reference voltage VEE and are connected in series, and a bias circuit 5. And are equipped with.

The bias circuit 5 includes four operational amplifiers OP.
1 to OP4, each operational amplifier OP1
Each of the voltage dividing resistors R1 is connected to the positive side input terminal of OP4.
The voltage at the connection point of ~ R5 is input.

The output terminals of the operational amplifiers OP1 to OP4 are fed back to their negative side input terminals and are connected to the output terminals of V1 to V4 of the power supply circuit 2 and the output terminal V0 of the power supply circuit 2. Is the reference voltage V
EE is input, and the reference voltage VSS is input to its output terminal V5.

The drive voltages V0 to V5 are output from the output terminals V0 to V5 of the power supply circuit 2 to the common driver 3 and the segment driver 4.

Specifically, the output terminal V0 and the output terminal V5 of the power supply circuit 2 are connected to both the common driver 3 and the segment driver 4, and the output terminal V1 and the output terminal V are connected.
The common driver 3 has an output terminal V2 and an output terminal V4.
3 are connected to the segment driver 4, respectively.

Therefore, the power supply circuit 2 has the reference voltage VEE.
The voltage between the reference voltage VSS and the reference voltage VSS is divided by the voltage dividing resistors R1 to R5, and the driving voltages V1 to OP1 are supplied via the operational amplifiers OP1 to OP4.
The reference voltage VEE is output as it is as the drive voltage V0, and the reference voltage VSS is output as it is as the drive voltage V5.

The power supply circuit 2 uses the generated drive voltage V0.
Of the drive voltages V0, V1, V4, and V5, the drive voltages V0, V2, V3, and V are supplied to the common driver 3.
5 is supplied to the segment driver 4.

The common driver 3 and the segment driver 4 are supplied with an alternating signal (a liquid crystal AC driving signal) M from a control circuit (not shown), and the segment driver 4 is supplied with display data. There is.

As described above, the common driver 3 receives a plurality of types of drive voltages V0, V1, V4, V from the power supply circuit 2.
5 is supplied to the common driver 3 based on the alternating signal M, and the drive voltages V0 and V supplied from the power supply circuit 2 are supplied.
One of 1, V4 and V5 is appropriately selected and sequentially supplied to the common line of the LCD, and the common line is selectively scanned.

Specifically, as shown in FIG. 9, the common driver 3 has selection circuits 3a to 3n as many as the number of LCD common lines, and each selection circuit 3a to 3n includes:
Drive voltages V0, V1, V4 supplied from the power supply circuit 2,
V5 is supplied through the internal power supply lines L0, L1, L4, L5.

Each of the selection circuits 3a to 3n is provided with four switches SW0, SW1, SW4 and SW5, and each switch SW0, SW1, SW4 and SW5 has
From the control circuit (not shown), the alternating signal M and the selection circuits 3a-3
An output control signal, which is a selection signal indicating whether n is in a selected state or a non-selected state, is input.

Each switch SW of each selection circuit 3a-3n
0, SW1, SW4 and SW5 are one of the switches SW0, SW1 and S based on this output control signal.
W4 and SW5 are turned on, and switches SW0 and SW that are turned on
1, drive voltages V0 and V input to SW4 and SW5
1, V4, V5 are output as drive signals to the common lines to which the selection circuits 3a to 3n are connected.

The output control signal input from this control circuit includes the alternating signal M, and each selection circuit 3
a to 3n switches SW0, SW1, SW4, SW5
Are drive voltages V0, V1, V4, in which the polarity of the voltage of the drive signal is inverted in accordance with the changing cycle of the alternating signal M.
Select V5.

As described above, the segment driver 4 has a plurality of driving voltages V0, V2, V from the power supply circuit 2 as described above.
3 and V5 are supplied, the segment driver 4 selects one of the drive voltages V0, V2, V3, and V5 supplied from the power supply circuit 2 based on the alternating signal M and the display data, and the selection is performed. Drive voltage V0, V2, V3, V5
The display drive signal of the voltage of is output to the segment line of the LCD.

Although not shown in detail, the segment driver 4 has a plurality of selection circuits like the common driver 3, and each selection circuit is based on the display data and the AC signal M input from the control circuit. One of the drive voltages V0, V2, V3, and V5 that are input as input is selected and output as a display drive signal to the segment line to which the selection circuit is connected.

Further, in particular, each selection circuit of the segment driver 4 receives the voltage of the display drive signal in response to the changing cycle of the alternating signal M by the alternating signal M as the output control signal input from the control circuit. The drive voltages V0, V2, V3, and V5 whose polarities are inverted are selected.

When a driving signal is supplied to the common line and the segment line from the common driver 3 and the segment driver 4, the liquid crystal at the intersection of the common line and the segment line is driven for display.

Since the common driver 3 and the segment driver 4 invert the polarity of the voltage of the drive signal based on the alternating signal M as described above, the LCD
Can be AC driven.

[0024]

However, in such a conventional liquid crystal driving device, all kinds of driving voltages used in the common driver and the segment driver are generated from the power supply circuit, and the common driver and the segment driver are respectively generated. The segment driver is supplied, and the common driver and the segment driver appropriately select from a plurality of drive voltages supplied from the power supply circuit to generate a drive signal and AC drive the LCD. Therefore, the power supply circuit, the common driver, and the segment driver In addition, it is necessary to wire the number of power supply lines corresponding to the number of drive voltages used by the common driver and the segment driver, and the common driver and the segment driver should be appropriately selected from the plurality of drive voltages supplied. A selection circuit to select is required.

As a result, the number of wires in the power line in the common driver or segment driver and between the power circuit and the common driver or segment driver increases, and
Since a selection circuit corresponding to the number of drive voltages is required, there is a problem that the liquid crystal drive device becomes large in size, mounting efficiency is deteriorated, current consumption is increased, and the number of parts is increased, resulting in high cost.

Therefore, the present invention has been made in view of the above circumstances, and uses a small number of power supply lines to switch the drive voltage required for AC driving of liquid crystal and supply the drive voltage from the power supply circuit to the drive circuit to reduce the size. It is an object of the present invention to provide a liquid crystal drive device that is inexpensive, has good mounting efficiency, and consumes less current.

[0027]

A liquid crystal driving device of the present invention includes a liquid crystal display panel in which liquid crystal is sealed between a pair of transparent substrates, and a plurality of scanning lines and signal lines are formed on the transparent substrate, and a predetermined liquid crystal display panel. A voltage generation unit that divides a reference voltage into a plurality of voltages to generate and provide a plurality of types of drive voltages, a control signal for driving display data of the display data on the liquid crystal display panel, and an AC drive for driving the liquid crystal display panel. A control signal generation unit that generates an AC drive signal and a voltage that drives the liquid crystal display panel are selected from the plurality of types of voltages provided from the voltage generation unit, and scanning drive that corresponds to the selected voltage is selected. A signal is selected from a plurality of kinds of voltages provided by the scanning signal generation means for providing a signal to the scanning line of the liquid crystal display panel and the voltage generation means, and the selected voltage corresponding to the selected voltage is selected. Display signal generating means for providing a display drive signal to a signal line of the liquid crystal display panel, the voltage generating means, the scanning signal generating means and the display signal generating means according to the AC drive signal, The above-mentioned object is achieved by selecting the predetermined voltage and supplying it to the scanning signal generating means and the display signal generating means.

In this case, for example, as described in claim 2, the voltage generating means selects the voltage dividing circuit for generating the plurality of types of voltages from the predetermined reference voltage and the plurality of types of voltages. A selection circuit, wherein at least one power supply line of the plurality of power supply lines respectively connected to the scanning signal generation means and the display signal generation means from the selection circuit is selected based on the AC drive signal. The plurality of generated voltages may be shared by the one power supply line to provide the predetermined voltage to the scanning signal selection means and the display signal generation means.

Further, for example, as described in claim 3, the scanning signal generating means selects the voltage for each scanning line from a plurality of voltages selectively provided from the voltage generating means based on the control signal. A display circuit is provided which has a selection circuit that selects a single predetermined voltage according to the scanning timing of a scan line and provides the selected voltage to the scan line as a scan drive signal. The means selects a single and predetermined voltage based on display data for each signal line from the plurality of voltages selectively provided from the voltage generation means based on the control signal, A selection circuit that provides the selected voltage to the signal line as the display drive signal may be included.

Further, for example, as described in claim 4, the voltage generating means is configured to provide the voltage drive circuit for each cycle of the AC drive signal from among the plurality of types of voltages provided by the voltage dividing circuit. It is also possible to select a predetermined number of types of voltage that is smaller than the number of the plurality of types of voltages to be provided, and to provide the selected voltage to each of the scanning signal generation means and the display signal generation means.

[0031]

According to the liquid crystal drive device of the present invention, the voltage generation means divides and provides a predetermined reference voltage into a plurality of voltages, and the scanning signal generation means uses the plurality of voltages supplied from the voltage generation means. A voltage for driving the display panel is selected, and a scan drive signal corresponding to the selected voltage is supplied to the scan line of the liquid crystal display panel. In addition, the display signal generation means,
A voltage is selected from a plurality of voltages supplied from the voltage generating means, and a display drive signal corresponding to the selected voltage is supplied to the signal line of the liquid crystal display panel. The control signal generation means generates a control signal for driving the display data to be displayed on the liquid crystal display panel and an AC drive signal for AC driving the liquid crystal display panel, and the voltage generation means causes the control signal generation means. The predetermined voltage is selected according to the AC drive signal generated by the above, and is supplied to the scanning signal generating means and the display signal generating means.

Therefore, the voltage required by the scanning signal generating means and the display signal generating means can be supplied to the scanning signal generating means and the display signal generating means by the power supply line which is smaller than the number of required voltages. Also in the scanning signal generating means and the display signal generating means, it is possible to supply the necessary voltage to each circuit in the scanning signal generating means and the display signal generating means with a small number of power supply lines. Moreover, only a small voltage needs to be selected in the scanning signal generating means and the display signal generating means, and the circuit configurations of the scanning signal generating means and the display signal generating means can be simplified and simplified.

As a result, the number of parts of the liquid crystal drive device can be reduced, and the liquid crystal drive device can be made compact, inexpensive, good in mounting efficiency, and low in current consumption.

In this case, for example, as described in claim 2, the voltage generating means includes a voltage dividing circuit that generates a plurality of types of voltages from a predetermined reference voltage, and a selection circuit that selects from the plurality of types of voltages. And at least one power supply line of the plurality of power supply lines respectively connected to the scanning signal generation means and the display signal generation means from the selection circuit, the selected plurality of voltages based on the AC drive signal. Is shared by the one power supply line to provide a predetermined voltage to the scanning signal selection means and the display signal generation means, the same voltage generation means as the conventional one can be used and the number of power supply lines can be increased. It is possible to provide a liquid crystal drive device that is smaller in size and less expensive.

Further, for example, as described in claim 3, the scanning signal generating means selects, for each scanning line, from a plurality of voltages selectively provided from the voltage generating means based on the control signal. Depending on whether it is the scanning timing of the scanning line, select a single and predetermined voltage,
The display signal generating means includes a selection circuit that provides the selected voltage to the scan line as a scan drive signal,
Based on the display data for each signal line, a single and predetermined voltage is selected from the plurality of voltages selectively supplied from the voltage generation means based on the control signal, and the selected voltage is selected. If a selection circuit that supplies a voltage to the signal line as a display drive signal is provided, the power supply lines in the scanning signal generation unit and the display signal generation unit can be reduced, and the selection circuit can be reduced. The liquid crystal drive device can be made even smaller and consume less current.

Further, for example, as described in claim 4, the voltage generating means is provided for each cycle of the AC drive signal from among a plurality of types of voltages provided by the voltage dividing circuit. A predetermined number of types of voltage that is smaller than the number of types of voltages to be applied to each of the scanning signal generating means and the display signal generating means,
If it is provided, the voltage generating means generates only the voltage that may be used by the scanning signal generating means and the display signal generating means in the period based on the AC driving signal, and the scanning signal generating means and the display signal are generated. The liquid crystal driving device can be supplied to the generating means, the number of parts such as the operational amplifier of the voltage generating means can be reduced, and the liquid crystal driving device can be further simplified and have a small structure.

[0037]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described below with reference to the drawings. 1 to 6 are views showing an embodiment of a liquid crystal drive device of the present invention, FIG. 1 is a schematic circuit block diagram of the liquid crystal drive device, and FIG. 2 is a power supply circuit of the liquid crystal drive device. FIG. 3 is a partial circuit diagram of a common driver of the liquid crystal driving device, FIG. 4 is a partial circuit diagram of a segment driver of the liquid crystal driving device, and FIG. 5 is a power supply for the common driver and the segment driver. FIG. 6 is a diagram showing the types of drive voltages supplied from the circuit and selected states of the drive voltages in the common driver and the segment driver, and FIG. 6 is a diagram showing the drive voltage and timing waveforms of the drive signals.

In FIG. 1, the liquid crystal drive device 10 includes a power supply circuit 11, a common driver 14, and a segment driver 15. The power supply circuit 11 includes voltage dividing circuits 12 and 4.
It is provided with one selection circuit 13a, 13b, 13c, 13d. The voltage dividing circuit 12 has a reference voltage VEE and a reference voltage VSS.
Has been entered.

The voltage dividing circuit 12 is the power supply circuit 1 shown in FIG.
Similarly, the reference voltage VEE and the reference voltage VSS are divided to generate the drive voltages V0 to V5, and the drive voltage V0 and the drive voltage V
1 is output to the selection circuit 13a, drive voltages V4 and V5 are output to the selection circuit 13b, drive voltages V3 and V0 are output to the selection circuit 13c, and drive voltages V5 and V2 are output to the selection circuit 13d.

The reference voltage VEE and the reference voltage VSS are VEE
> VSS, and usually VEE = -VSS.

An alternating signal M for alternating-current driving the liquid crystal is inputted to the selection circuits 13a to 13d from a control circuit (not shown), and the selection circuits 13a and 13b are
The common driver 14 includes a selection circuit 13c and a selection circuit 13
d is connected to the segment driver 15.

The selection circuit 13a selects one of the driving voltage V0 and the driving voltage V1 input from the voltage dividing circuit 12 based on the alternating signal M and outputs it to the common driver 14, and the selection circuit 13b. Selects one of the drive voltage V4 and the drive voltage V5 input from the voltage dividing circuit 12 based on the alternating signal M and outputs the selected voltage to the common driver 14.

The selection circuit 13c selects one of the driving voltage V3 and the driving voltage V0 input from the voltage dividing circuit 12 based on the alternating signal M and outputs the selected segment driver 15 to the segment driver 15. The segment driver 13d selects one of the drive voltage V5 and the drive voltage V2 input from the voltage dividing circuit 12 on the basis of the alternating signal M and selects the segment driver 15.
Output to. This alternating signal M is, as shown in FIG.
It is a signal that periodically changes between a high level (“1”) and a low level (“0”).

The power supply circuit 11 is specifically constructed as shown in FIG. That is, the voltage divider selection circuit 11a, 11b, 11c, 11d is composed of four voltage division selection circuits 11a, 11b, 11c, and 11d, and the voltage division selection circuit 11a includes a part of the voltage division circuit 12 and the selection circuit 13a. 1, a part of the voltage dividing circuit 12 and the selecting circuit 13b, a voltage dividing selecting circuit 11c, a part of the voltage dividing circuit 12 and the selecting circuit 13c of FIG. 1, and a voltage dividing selecting circuit 11d. 1 voltage divider circuit 12
And a selection circuit 13d.

That is, the voltage dividing selection circuit 11a includes an inverter In1, a resistor r1, and voltage dividing resistors R11, R12, R1.
3, the transistor Tr1 and the operational amplifier OP11 are provided. The voltage dividing resistors R11, R12, R13 are connected in series, and the reference voltage VEE and the reference voltage VSS are input to the voltage dividing resistors R11 and R13 at both ends thereof. Has been done.

The AC signal M is input to the base of the transistor Tr1 via the inverter In1 and the resistor r1, and the emitter of the transistor Tr1 has a voltage dividing resistor R11.
And the collector of the transistor Tr1 are connected to the connection point of the voltage dividing resistor R12 and the voltage dividing resistor R12, respectively.

The connection point of the voltage dividing resistors R12 and R13 to which the collector of the transistor Tr1 is connected is connected to the positive side input terminal of the operational amplifier OP11, and the output terminal of the operational amplifier OP11 is an operational amplifier. It is connected to the negative side input terminal of OP11 and also to the V0 / V1 output terminal of the power supply circuit 11. The V0 / V1 output terminal of the power supply circuit 11 is
It is connected to the common driver 14.

Therefore, the voltage division selection circuit 11a inverts the AC signal M by the inverter In1 and inputs it to the base of the transistor Tr1 via the resistor r1, and the transistor Tr1 is operated when the AC signal M is "1". Since the alternating signal M is inverted by the inverter In1, it is turned on and the emitter and collector of the transistor Tr1 are short-circuited.

Therefore, at this time, the operational amplifier OP11
A divided voltage corresponding to the drive voltage V0 obtained by dividing the reference voltage VEE and the reference voltage VSS by the voltage dividing resistors R11 and R13 connected in series is input to the operational amplifier OP1.
1 outputs the drive voltage V0 to the common driver 14 via the V0 / V1 output terminal.

Further, in the voltage division selection circuit 11a, when the AC signal M is "0", the transistor Tr1 is turned off and the emitter and collector of the transistor Tr1 are opened. Therefore, the reference voltage VEE and the reference voltage The divided voltage corresponding to the drive voltage V1 divided by the voltage dividing resistors R11, R12, and R13 connected in series with VSS is input to the operational amplifier OP11, and the operational amplifier OP11 outputs the drive voltage V1 to V0 / V.
It outputs to the common driver 14 via 1 output terminal.

That is, the voltage division selection circuit 11a outputs the driving voltage V0 to the common driver 14 when the alternating signal M is "1", and the driving voltage V1 is common when the alternating signal M is "0". Output to the driver 14.

The voltage dividing selection circuit 11b is a non-inverter N
In1, resistors r2, r3, r4, voltage dividing resistors R14, R1
5, R16, transistors Tr2, Tr3, operational amplifier OP12, etc., and voltage dividing resistors R14, R15,
R16 is connected in series, and the reference voltage VEE and the reference voltage V are applied to the voltage dividing resistors R14 and R15 at both ends thereof.
SS is input.

The base of the transistor Tr3 is a resistor r3.
Is connected to the collector of the transistor Tr2 via, and the AC signal M is input to the base of the transistor Tr2 via the non-inverter NIn1 and the resistor r2. The emitter of the transistor Tr2 is connected to the reference voltage VEE.

The collector of the transistor Tr3 is connected to the connection point of the voltage dividing resistors R14 and R15,
The emitter of the transistor Tr3 is connected to the connection point of the voltage dividing resistor R15 and the voltage dividing resistor R16, and is also connected to its base via the resistor r4.

The connection point of the voltage dividing resistors R14 and R15, to which the collector of the transistor Tr3 is connected, is connected to the plus side input terminal of the operational amplifier OP12, and the output terminal of the operational amplifier OP12 is an operational amplifier. It is connected to the negative side input terminal of OP12 and also to the V4 / V5 output terminal of the power supply circuit 11. The V4 / V5 output terminal of the power supply circuit 11 is
It is connected to the common driver 14.

Therefore, the voltage division selection circuit 11b inputs the AC signal M to the base of the transistor Tr2 via the non-inverter NIn1 and the resistor r2, and the transistor Tr2 outputs this signal when the AC signal M is "0". Since the alternating signal M is not inverted by the non-inverter NIn1, it is turned on.

When the transistor Tr2 is on, a base current flows through the base of the transistor Tr3, the transistor Tr3 is also turned on, and the emitter and collector of the transistor Tr3 are short-circuited.

Therefore, the operational amplifier OP12 has a voltage dividing resistor R in which the reference voltage VEE and the reference voltage VSS are connected in series.
The divided voltage corresponding to the driving voltage V5 divided by the voltage dividing resistor R16 and the voltage dividing resistor R16 is input, and the operational amplifier OP12 outputs the driving voltage V5 to the common driver 14 via the V4 / V5 output terminal.

In the voltage division selection circuit 11b, when the alternating signal M is "1", the transistor Tr2 is turned off, the transistor Tr3 is also turned off, and the transistor T is turned off.
The emitter and collector of r3 are open.

Therefore, the reference voltage VEE and the reference voltage VSS
The divided voltage corresponding to the driving voltage V4 divided by the voltage dividing resistors R14, R15, and R16 connected in series is input to the operational amplifier OP12, and the operational amplifier OP12 outputs the driving voltage V4 via the V4 / V5 output terminals. Common driver 14
Output to.

That is, the voltage dividing selection circuit 11b outputs the drive voltage V5 to the common driver 14 when the alternating signal M is "0", and the drive voltage V4 is common when the alternating signal M is "1". Output to the driver 14.

The voltage division selection circuit 11c is a non-inverter N.
In2, resistor r5, voltage dividing resistors R17, R18, R19,
The transistor Tr4 and the operational amplifier OP13 are provided, and the voltage dividing resistors R17, R18, and R19 are connected in series, and the reference voltage VEE and the reference voltage VSS are input to the voltage dividing resistors R17 and R19 at both ends thereof. ing.

The AC signal M is input to the base of the transistor Tr4 via the non-inverter NIn2 and the resistor r5, and the emitter of the transistor Tr4 has a voltage dividing resistor R1.
7 is connected to the connection point of the voltage dividing resistor R18, and the collector of the transistor Tr4 is connected to the connection point of the voltage dividing resistor R18 and the voltage dividing resistor R19.

The connection point of the voltage dividing resistors R18 and R19, to which the collector of the transistor Tr4 is connected, is connected to the plus side input terminal of the operational amplifier OP13, and the output terminal of the operational amplifier OP13 is an operational amplifier. It is connected to the negative side input terminal of OP13 and also to the V3 / V0 output terminal of the power supply circuit 11. The V3 / V0 output terminal of this power supply circuit 11 is
It is connected to the segment driver 15.

Therefore, the voltage division selection circuit 11c inputs the AC signal M to the base of the transistor Tr4 via the non-inverter NIn2 and the resistor r5. When the AC signal M is "0", the transistor Tr4 outputs this signal. Since the AC signal M is not inverted by the non-inverter NIn2, it is turned on and the emitter and collector of the transistor Tr4 are short-circuited.

Therefore, at this time, the operational amplifier OP13
A divided voltage corresponding to the drive voltage V0 obtained by dividing the reference voltage VEE and the reference voltage VSS by the voltage dividing resistors R17 and R19 connected in series is input to the operational amplifier OP1.
3 outputs this drive voltage V0 to the segment driver 15 via the V3 / V0 output terminal.

Further, in the voltage division selection circuit 11c, when the alternating signal M is "1", the transistor Tr4 is turned off and the emitter and collector of the transistor Tr4 are opened, so that the reference voltage VEE and the reference voltage The divided voltage corresponding to the drive voltage V3 divided by the voltage dividing resistors R17, R18, and R19 connected in series with VSS is input to the operational amplifier OP13, and the operational amplifier OP13 outputs the drive voltage V3 to V3 / V.
Output to the segment driver 15 via the 0 output terminal.

That is, the voltage division selection circuit 11c outputs the driving voltage V0 to the segment driver 15 when the alternating signal M is "0", and the driving voltage V3 is segmented when the alternating signal M is "1". Output to the driver 15.

The voltage dividing selection circuit 11d is provided with an inverter In
2, resistors r6, r7, r8, voltage dividing resistors R20, R21,
R22, transistors Tr5, Tr6 and operational amplifier O
It is equipped with P14, etc., and has voltage dividing resistors R20, R21, R2.
2 is connected in series and has a voltage dividing resistor R at both ends thereof.
The reference voltage VEE and the reference voltage VSS are input to the voltage dividing resistor R22 and the voltage dividing resistor R22.

The base of the transistor Tr5 is a resistor r7.
Is connected to the collector of the transistor Tr5 via a transistor Tr5, and the base of the transistor Tr5 has an inverter In
The AC signal M is input via 2 and the resistor r6. The emitter of the transistor Tr5 is connected to the reference voltage VEE.

The collector of the transistor Tr6 is connected to the connection point of the voltage dividing resistors R20 and R21,
The emitter of the transistor Tr6 is connected to the connection point of the voltage dividing resistor R21 and the voltage dividing resistor R22, and is also connected to its base via the resistor r8.

The connection point of the voltage dividing resistors R20 and R21 connected to the collector of the transistor Tr6 is connected to the plus side input terminal of the operational amplifier OP14, and the output terminal of the operational amplifier OP14 is an operational amplifier. It is connected to the negative side input terminal of OP14 and also to the V5 / V2 output terminal of the power supply circuit 11. The V5 / V2 output terminal of the power supply circuit 11 is
It is connected to the segment driver 15.

Therefore, the voltage division selection circuit 11d inputs the alternating signal M to the base of the transistor Tr5 via the inverter In2 and the resistor r6, and the transistor Tr5 is inputted.
5 is the alternating signal M when the alternating signal M is "1".
Is inverted by the inverter In1 and becomes "0".
It turns on.

When the transistor Tr5 is on, a base current flows through the base of the transistor Tr6, the transistor Tr6 is also turned on, and the emitter and collector of the transistor Tr6 are short-circuited.

Therefore, the operational amplifier OP14 has a voltage dividing resistor R in which the reference voltage VEE and the reference voltage VSS are connected in series.
The divided voltage corresponding to the drive voltage V5 divided by 20 and the voltage dividing resistor R22 is input, and the operational amplifier OP14 outputs the drive voltage V5 to the segment driver 15 via the V5 / V2 output terminal.

In the voltage division selection circuit 11d, when the alternating signal M is "0", the transistor Tr5 is turned off, the transistor Tr6 is also turned off, and the transistor T is turned off.
The emitter and collector of r6 are open.

Therefore, the reference voltage VEE and the reference voltage VSS
The divided voltage corresponding to the drive voltage V2 divided by the voltage dividing resistors R20, R21, and R22 connected in series is input to the operational amplifier OP14, and the operational amplifier OP14 outputs the drive voltage V2 via the V5 / V2 output terminal. Output to the segment driver 15.

That is, the voltage division selection circuit 11d outputs the driving voltage V5 to the segment driver 15 when the alternating signal M is "1", and the driving voltage V2 is segmented when the alternating signal M is "0". Output to the driver 15.

As shown in FIG. 3, the common driver 14 has as many selection circuits 14a as the number of common lines of the LCD.
To 14n, each of the selection circuits 14a to 14n has
It is connected to the common line of the LCD. Each selection circuit 1
The drive voltage V0 / V1 and the drive voltage V4 / V5 supplied from the power supply circuit 11 are supplied to 4a to 14n through the internal power supply lines L11 and L12.

Each of the selection circuits 14a to 14n has the same circuit configuration and has two switches SW1.
1, SW12, an inverter In11, and a non-inverter NIn11.

The switch SW11 has a drive voltage V0 / V1.
Is connected to a power supply line L11 for supplying
Connected to the CD common line, switch SW1
2 is a power supply line L12 for supplying the drive voltage V4 / V5
And to the common line of the LCD.

An output control signal from a control circuit (not shown) is input to the switch SW11 of each of the selection circuits 14a to 14n via a non-inverter NIn11 and an inverter In11, and the switch SW12 receives the output control signal of a non-input state. It is input via the inverter NIn11.

This output control signal corresponds to the selection circuit 14a.
Selection / non-selection signals for controlling the selection timing and non-selection timing of the connected common lines of
The switch SW11 and the switch SW12 are turned on when the input output control signal is "1", and the connected power supply line L11 or power supply line L12 is set to L.
Connect to the CD common line.

Therefore, in each of the selection circuits 14a to 14n of the common driver 14, either the switch SW11 or the switch SW12 is turned on and turned on depending on whether the output control signal is "1" or "0". Switch SW1
1 or the drive voltage V0 or the drive voltage V1 or the drive voltage V4 being input to the switch SW12 at that time.
One of the driving voltages V5 is selected and supplied to the common line of the LCD.

As shown in FIG. 4, the segment driver 15 has selection circuits 15a to 15m as many as the number of LCD segment lines, and the selection circuits 15a to 1m.
5 m is connected to the common line of the LCD. The drive voltage V3 / V0 and the drive voltage V5 / V2 supplied from the power supply circuit 11 are supplied to the selection circuits 15a to 15m through the internal power supply lines L21 and L22.

Each of the selection circuits 15a to 15m has the same circuit configuration and has two switches SW2.
1, SW22, inverter In21 and non-inverter NIn21.

The switch SW21 has a drive voltage V3 / V0.
Is connected to the power supply line L21 for supplying
Connected to the common line of CD, switch SW2
2 is a power supply line L22 for supplying the drive voltage V5 / V2
And the segment line of the LCD.

In each of the selection circuits 15a to 15m, an output control signal is input to a switch SW21 from a control circuit (not shown) via a non-inverter NIn21 and an inverter In21, and the switch SW22 outputs the output control signal to a non-switch. It is input via the inverter NIn21.

This output control signal corresponds to the selection circuit 15a.
Display data corresponding to connected segment lines of ˜15 m, and includes switch SW21 and switch SW22.
Is turned on when the input output control signal (display data) is "1", and the connected power supply line L21
Alternatively, the power line L22 is connected to the LCD segment line.

Therefore, each of the selection circuits 15a to 15m of the segment driver 15 is turned on by turning on either the switch SW21 or the switch SW22 depending on whether the output control signal is "1" or "0". Switch S
One of the driving voltage V3 or the driving voltage V0 or the driving voltage V5 or the driving voltage V2 which is being input to W21 or the switch SW22 at that time is selected and supplied to the segment line of the LCD.

That is, as shown in FIG. 5, when the AC signal M is "0", the common driver 14 is supplied with the drive voltage V5 and the drive voltage V1 from the power supply circuit 11, and the segment driver 15 is supplied with the drive voltage V5. The drive voltage V0 and the drive voltage V2 are supplied. When the alternating signal M is "1", the power supply circuit 11 supplies the common driver 14 with the drive voltage V0 and the drive voltage V4, and the segment driver 15 receives the drive voltage V5 and the drive voltage V3. To be done.

In each of the selection circuits 14a to 14n of the common driver 14, the output control signal is "1" when the alternating signal M is "0" and the drive voltage V5 and the drive voltage V1 are supplied. Then, the drive voltage V5 is selected and supplied to the common line. When the output control signal is "0", the drive voltage V1 is selected and supplied to the common line.

When the alternating signal M is "1" and the drive voltage V0 and the drive voltage V4 are supplied, if the output control signal is "1", the drive voltage V0 is selected and the common line is selected. When the output control signal is "0", the drive voltage V4 is selected and supplied to the common line.

Further, in each of the selection circuits 15a to 15m of the segment driver 15, the output control signal is "1" when the alternating signal M is "0" and the drive voltage V0 and the drive voltage V2 are supplied. Then, the drive voltage V0 is selected and supplied to the segment line. When the output control signal is "0", the drive voltage V2 is selected and supplied to the segment line.

Further, in each of the selection circuits 15a to 15m of the segment driver 15, the output control signal is "1" when the alternating signal M is "1" and the drive voltage V5 and the drive voltage V3 are supplied. Then, the drive voltage V5 is selected and supplied to the segment line. When the output control signal is "0", the drive voltage V3 is selected and supplied to the segment line.

Next, the operation of this embodiment will be described. In the liquid crystal drive device of this embodiment, the power supply circuit 11 simultaneously generates all the drive voltages V0 to V5 required by the common driver 14 and the segment driver 15 and outputs them to the common driver 14 and the segment driver 15. Instead, only the drive voltages V0 to V5 required in the cycle of the alternating signal M are selected and generated based on the alternating signal M, and are supplied to the common driver 14 and the segment driver 15 to supply the common driver 14 and the segment. The driver 15 is characterized in that it selects and uses the drive voltages V0 to V5 required for display from the supplied drive voltages V0 to V5.

That is, the power supply circuit 11 is provided with four voltage division selection circuits 11a to 11d as shown in FIG. 2, and the voltage division selection circuit 11a has a driving voltage V0 and a driving voltage V0.
1, the voltage division selection circuit 11b outputs the drive voltage V4 and the drive voltage V5, the voltage division selection circuit 11c outputs the drive voltage V3 and the drive voltage V0, and the voltage division selection circuit 11c outputs the drive voltage V5 and the drive voltage V2. , Each of which is selectively generated based on the alternating signal M.

Specifically, in the voltage division selection circuit 11a, when the alternating signal M is "1", the alternating signal M is inverted by the inverter In1 and input to the base of the transistor Tr1 to turn on the transistor Tr1. Then, the divided voltage obtained by dividing the reference voltage VEE and the reference voltage VSS by the voltage dividing resistor R11 and the voltage dividing resistor R13 is supplied to the common driver 1 as the driving voltage V0 as shown in FIG. 6 via the operational amplifier OP11.
4 is output.

Further, in the voltage division selection circuit 11a, when the alternating signal M is "0", the transistor Tr1 is turned off, and the reference voltage VSS and the reference voltage VSS are divided into resistors R11, R12, R.
The divided voltage divided by 13 is output to the common driver 14 via the operational amplifier OP11 as the drive voltage V1 as shown in FIG.

That is, the voltage division selection circuit 11a supplies the drive voltage V0 to the common driver 14 when the alternating signal M is "1", and the drive voltage V1 is common when the alternating signal M is "0". Supply to the driver 14.

When the AC conversion signal M is "0", the voltage division selection circuit 11b inputs the AC conversion signal M as it is to the transistor Tr2 through the non-inverter NIn1 and turns on the transistor Tr2. The transistor Tr3 turns on. Therefore, the voltage division selection circuit 1
1b shows the divided voltage obtained by dividing the reference voltage VEE and the reference voltage VSS by the voltage dividing resistors R14 and R16 when the AC signal M is "0", via the operational amplifier OP12, and shown in FIG. As described above, the driving voltage V5 is supplied to the common driver 14.

Further, in the voltage dividing selection circuit 11b, when the alternating signal M is "1", the transistors Tr2 and Tr3 are turned off, and the reference voltage VEE and the reference voltage VSS are divided by the voltage dividing resistors R14, R15 and R16. The divided voltage thus divided is passed through the operational amplifier OP12, as shown in FIG.
The drive voltage V4 is supplied to the common driver 14.

That is, the voltage dividing selection circuit 11b supplies the drive voltage V5 to the common driver 14 when the alternating signal M is "0", and the drive voltage V4 is common when the alternating signal M is "1". Supply to the driver 14.

Further, in the voltage dividing selection circuit 11c, when the alternating signal M is "0", the transistor Tr4 is turned on, and the reference voltage VEE and the reference voltage VSS are divided into the voltage dividing resistors R17 and R.
The divided voltage divided by 19 is supplied to the segment driver 15 via the operational amplifier OP13 as the drive voltage V0 as shown in FIG.

Further, in the voltage dividing selection circuit 11c, when the alternating signal M is "1", the transistor Tr4 is turned off, and the reference voltage VEE and the reference voltage VSS are divided into voltage dividing resistors R17, R18,
The divided voltage divided by R19 is supplied to the segment driver 15 as the driving voltage V3 via the operational amplifier OP13 as shown in FIG.

That is, the voltage division selection circuit 11c supplies the drive voltage V0 to the segment driver 15 when the alternating signal M is "0", and the drive voltage V3 is segmented when the alternating signal M is "1". Supply to the driver 15.

Further, when the AC conversion signal M is "1", the voltage division selection circuit 11d outputs the AC conversion signal M to the inverter In.
Since it is inverted at 2 and input to the base of the transistor Tr5, the transistor Tr5 is turned on and the transistor T5 is turned on.
r6 turns on. Therefore, the voltage division selection circuit 11d
When the alternating signal M is "1", the divided voltage obtained by dividing the reference voltage VEE and the reference voltage VSS by the voltage dividing resistors R20 and R22 is supplied via the operational amplifier OP14 as shown in FIG. The drive voltage V5 is supplied to the segment driver 15.

Further, in the voltage dividing selection circuit 11d, when the AC signal M is "0", the transistor Tr5 is turned off and the transistor Tr6 is turned off. Therefore, the reference voltage VEE and the reference voltage VSS are divided into voltage dividing resistors R20 and R21. , R22, the divided voltage is supplied to the segment driver 15 via the operational amplifier OP14 as the driving voltage V2 as shown in FIG.

That is, the voltage dividing selection circuit 11d supplies the driving voltage V5 to the segment driver 15 when the alternating signal M is "1", and the driving voltage V2 when the alternating signal M is "0". Supply to the driver 15.

As described above, the power supply circuit 11 switches the drive voltage V0 and the drive voltage V1 and the drive voltage V4 and the drive voltage V5 to the common driver 14 based on the alternating signal M, and supplies them to the segment driver 15. , Drive voltage V3
The drive voltage V0 and the drive voltage V5 and the drive voltage V2 are switched and supplied.

That is, as shown in FIG. 5, the power supply circuit 1
No. 1 supplies the common driver 14 with the drive voltage V0 and the drive voltage V4 and the segment driver 15 with the drive voltage V5 and the drive voltage V3 when the AC signal M is "0". When it is “1”, the common driver 14 is supplied with the driving voltage V5 and the driving voltage V1, and the segment driver 15 is supplied with the driving voltage V0 and the driving voltage V2.

In the power supply circuit 11, by appropriately setting the resistance values of the voltage dividing resistors R14 to R22,
The drive voltages V0 to V5 related to the voltage shown in FIG. 6 can be generated.

For example, as shown at the bottom of FIG. 6, when the bias for generating the offset from the intermediate voltage of the liquid crystal drive signal is set to 1 / α, the voltage dividing resistors R11 to R22.
The resistance ratio of R11: R12: R13: R14: R1
5: R16: R17: R18: R19: R20: R2
1: R22 = 1: α / (α-2) :( α-1) :( α-
1): α / (α-2): 1: 1: 11α / (α-1)
2): (α-1): (α-1): 11α / (α-1)
By setting the relationship 2): 1, it is possible to apply a liquid crystal drive signal having an effective voltage (VOP) relationship as shown at the bottom of FIG. 6 to the liquid crystal.

Therefore, the power supply circuit 11, the common driver 14, and the segment driver 15 need only be connected by two power supply lines each as shown in FIG. 1, and the number of power supply lines can be reduced. it can. In addition, operational amplifiers OP11 to OP14 in the power supply circuit 11
Also, the number of drive voltages V0 to V5 generated at the same time, that is, only four, is sufficient, and the operational amplifiers OP11 to OP14 are provided.
Can be reduced.

As a result, the power supply circuit 11 has a reduced number of parts, is small in size, inexpensive and consumes less current.
The mounting efficiency can be improved, the number of power supply lines can be reduced, and the mounting efficiency of the liquid crystal drive device can be improved.

Then, as shown in FIG. 3, the common driver 14 includes the selection circuits 14a to 14d corresponding to the number of common lines.
14n, and two types of drive voltage V1 and drive voltage V5 or drive voltage V0 selectively supplied from the power supply circuit 11 by two power supply lines L11 and L12.
And the drive voltage V4 are supplied to each of the selection circuits 14a to 14n.

The selection circuits 14a to 14n have the above-mentioned two types of drive voltage V1 and drive voltage V5, or drive voltage V5.
Select one drive voltage from 0 and drive voltage V4
It is selected by the output control signal which is a non-selection signal and is supplied to the common line of the LCD as a drive signal as shown in FIG.

Further, as shown in FIG. 4, the segment driver 15 includes the selection circuits 15 corresponding to the number of segment lines.
a to 15 m, and two kinds of drive voltages V3 selectively supplied from the power supply circuit 11 by two power supply lines.
And drive voltage V0, or drive voltage V5 and drive voltage V
2 is supplied to each of the selection circuits 15a to 15m.

Each of the selection circuits 15a to 15m includes a drive voltage V3 and a drive voltage V0 of the above two types, or a drive voltage V0.
One of the drive voltage V5 and the drive voltage V2 is selected by the output control signal which is display data and is supplied to the segment line of the LCD as a display drive signal as shown in FIG.

Therefore, as shown in FIG. 6, an effective voltage corresponding to the difference between the drive signal from the common driver 14 and the display drive signal from the segment driver 15 is applied to the LCD as a liquid crystal drive signal. The liquid crystal drive signal is AC-driven by reversing its polarity in response to the AC signal M.

As described above, in the common driver 14 and the segment driver 15, the number of the drive voltages V0 to V5 simultaneously supplied from the power supply circuit 11 is reduced, so that the number of the internal power supply lines L11, L12, L21, L22 is reduced. Can be reduced. Further, it is possible to reduce the number of switches SW11, SW12, SW21, SW22 of the selection circuits 14a to 14n and 15a to 15m for selecting the drive voltages V0 to V5, and further, these switches SW1.
As the output control signal for controlling ON / OFF of 1, SW12, SW21, and SW22, only the selection / non-selection signal or the display data may be used, and it is not necessary to consider the AC signal M as in the conventional case.

Therefore, the number of parts of the common driver 14 and the segment driver 15 can be reduced,
The common driver 14 and the segment driver 15 can be made small, inexpensive, consume little current, and have good mounting efficiency.

FIG. 7 is a diagram showing another embodiment of the liquid crystal driving device of the present invention, in which all the driving voltages used in the common driver and the segment driver are simultaneously generated by the power supply circuit, and the generated driving voltage is It is selected based on the alternating signal and output to the common driver and the segment driver.

That is, the liquid crystal drive device 20 of this embodiment.
Includes a power supply circuit 21, a common driver 22, and a segment driver 23. The power supply circuit 21 includes voltage dividing resistors R30, R31, R32, R33, R34, and a switch S.
W30, SW31, SW32, SW33, inverter I
n30, operational amplifiers OP30, OP31 and the like.

The reference voltage VEE and the reference voltage VSS are input to the power supply circuit 21, and the voltage dividing resistors R30 to R34 connected in series are connected between the reference voltage VEE and the reference voltage VSS.

Switches SW30 to SW33 are connected to the connection points of the voltage dividing resistors R30 to R34, respectively. The drive voltage V1 is applied to the switch SW30, the drive voltage V2 is applied to the switch SW31, and the switch SW32 is applied. Is the drive voltage V3, and the switch SW33 has
The driving voltage V4 is divided by the voltage dividing resistors R30 to R34 and input.

The switches SW30 and SW33 are
The output terminal is commonly connected and is connected to the plus side input terminal of the operational amplifier OP30.
The output terminal of is connected to the input terminals of the drive voltage V1 and the drive voltage V4 of the common driver 22, and is fed back to the negative input terminal of the operational amplifier OP30.

Also, the switch SW31 and the switch SW3
2, the output terminals of the operational amplifier OP are commonly connected.
The output terminal of the operational amplifier OP31 is connected to the input terminals of the driving voltage V2 and the driving voltage V3 of the segment driver 23 and is fed back to the negative input terminal of the operational amplifier OP31. There is.

The alternating signal M is input to the switches SW30 and SW31 via the inverter In30, and the alternating signal M is input to the switches SW32 and SW33 as it is. These switches S
The input AC signal M of W30 to SW33 is "1".
At this time, it is turned on and the input divided voltage is output to the operational amplifier OP30 or operational amplifier OP31, respectively.

Therefore, when the AC signal M is "1", the power supply circuit 21 switches SW32 and SW3.
3 is turned on, the drive voltage V3 is input to the operational amplifier OP31 via the switch SW32, and the drive voltage V4 is input to the operational amplifier OP30 via the switch SW33.

Further, in the power supply circuit 21, when the alternating signal M is "0", the switch SW30 and the switch SW31 are turned on, the drive voltage V1 is supplied to the operational amplifier OP30 via the switch SW30, and the drive voltage is supplied via the switch SW31. V2 is input to the operational amplifier OP31.

As a result, the power supply circuit 21 receives the alternating signal M
Is “0”, the drive voltage V1 is set to the common driver 22.
Then, the drive voltage V2 is supplied to the segment driver 23,
When the alternating signal M is "1", the drive voltage V4 is applied to the common driver 22, and the drive voltage V3 is applied to the segment driver 23.
Supply to.

Further, the power supply circuit 21 uses the reference voltage VEE as it is as the drive voltage V0 and the reference voltage VSS as it is as the drive voltage V5, and the common driver 2 respectively.
2 and the segment driver 23.

The AC signal M is input to the common driver 22, and the input terminals for the drive voltage V1 and the drive voltage V4 are switched based on the AC signal M to drive the drive voltage V1 and the drive voltage V5, or , The drive voltage V4 and the drive voltage V0 are selectively used and are supplied as a drive signal to the common line of the LCD.

Further, the AC signal M is input to the segment driver 23, and the input terminals for the drive voltage V2 and the drive voltage V3 are switched based on the AC signal M to drive the drive voltage V2 and the drive voltage V0. Alternatively, the drive voltage V3 and the drive voltage V5 are selectively used and supplied as a display drive signal to the segment line of the LCD.

Therefore, in this embodiment, the common driver 22 and the segment driver 2 are connected by the two operational amplifiers OP30 and OP31 via the two power supply lines.
It is possible to supply two driving voltages V1 / V4 and two driving voltages V2 / V3 to the liquid crystal driving device 20.
The number of circuit components can be reduced, and the liquid crystal drive device 20 can be made small and inexpensive.

Further, as the voltage dividing resistors R30 to R34, the conventional power supply circuit can be used as it is, and the liquid crystal drive device 20 can be made more inexpensive.

Although the invention made by the present inventor has been specifically described based on the preferred embodiments, the present invention is not limited to the above embodiments, and various modifications can be made without departing from the scope of the invention. Needless to say.

For example, in each of the above embodiments, the case where five types of drive voltages are generated, selected based on the alternating signal and supplied to the common driver and the segment driver has been described. Drive voltage is 5
It is not limited to types.

[0140]

According to the liquid crystal drive device of the present invention, the voltage generating means divides and provides a predetermined reference voltage into a plurality of voltages, and the scanning signal generating means supplies a plurality of voltages supplied from the voltage generating means. A voltage for driving the liquid crystal display panel is selected from among, and a scan drive signal corresponding to the selected voltage is supplied to the scan line of the liquid crystal display panel. Further, the display signal generation means selects a voltage from the plurality of voltages supplied from the voltage generation means, and supplies a display drive signal corresponding to the selected voltage to the signal line of the liquid crystal display panel. The control signal generation means generates a control signal for driving the display data to be displayed on the liquid crystal display panel and an AC drive signal for AC driving the liquid crystal display panel, and the voltage generation means causes the control signal generation means. The predetermined voltage is selected according to the AC drive signal generated by the above, and is supplied to the scanning signal generating means and the display signal generating means.

Therefore, the voltage required by the scanning signal generating means and the display signal generating means can be supplied to the scanning signal generating means and the display signal generating means by the power supply line which is smaller than the number of the necessary voltages. Also in the scanning signal generating means and the display signal generating means, it is possible to supply the necessary voltage to each circuit in the scanning signal generating means and the display signal generating means with a small number of power supply lines. Moreover, only a small voltage needs to be selected in the scanning signal generating means and the display signal generating means, and the circuit configurations of the scanning signal generating means and the display signal generating means can be simplified and simplified.

As a result, the number of parts of the liquid crystal driving device can be reduced, and the liquid crystal driving device can be made small, inexpensive, good in mounting efficiency, and low in current consumption.

In this case, as described in claim 2, the voltage generating means includes a voltage dividing circuit for generating a plurality of types of voltages from a predetermined reference voltage, and a selection circuit for selecting from the plurality of types of voltages. At least one power supply line of the plurality of power supply lines respectively connected to the scanning signal generation means and the display signal generation means from the selection circuit supplies the selected plurality of voltages based on the AC drive signal. If one power supply line is shared and a predetermined voltage is provided to the scanning signal selection means and the display signal generation means, the same voltage generation means as the conventional one can be used and the number of power supply lines can be further reduced. Can be even less,
It is possible to provide a smaller and cheaper liquid crystal drive device.

Further, according to a third aspect of the invention, the scanning signal generating means is arranged so that each scanning line is selected from a plurality of voltages selectively provided by the voltage generating means based on the control signal. The display signal generating means has a selection circuit that selects a single and predetermined voltage according to whether or not the scanning timing is and provides the selected voltage to the scanning line as a scanning drive signal. A single and predetermined voltage is selected from the plurality of voltages selectively supplied from the voltage generation means based on the control signal based on display data for each signal line, and the selection is performed. If a selection circuit for providing the selected voltage to the signal line as a display drive signal is provided, the power supply lines in the scanning signal generating means and the display signal generating means can be reduced, and the selection can be performed. It is possible to reduce the road, even more liquid crystal drive device, small in size, can be of small construction current consumption.

Further, as described in claim 4, the voltage generating means is configured to provide the plurality of voltages provided from the plurality of types of voltages provided by the voltage dividing circuit for each cycle of the AC drive signal. By selecting a predetermined number of types of voltage that is smaller than the number of types of voltages and providing the selected voltage to each of the scanning signal generation means and the display signal generation means, the voltage generation means performs AC drive. It is possible to generate only the voltage that may be used by the scanning signal generating means and the display signal generating means in the period based on the use signal and supply the voltage to the scanning signal generating means and the display signal generating means. The number of parts such as operational amplifiers can be reduced, and the liquid crystal drive device can be made simpler and have a smaller structure.

[Brief description of drawings]

FIG. 1 is a schematic circuit block diagram of an embodiment of a liquid crystal driving device of the present invention.

FIG. 2 is a detailed circuit diagram of the power supply circuit shown in FIG.

FIG. 3 is a partial circuit diagram of the common driver of FIG.

FIG. 4 is a partial circuit diagram of the segment driver of FIG.

5 is a selection diagram of a drive voltage supplied from the power supply circuit of FIG. 1 and a drive voltage for the segment driver and the common driver.

FIG. 6 is a timing chart of drive voltages and drive signals of respective parts of the liquid crystal drive device of FIG.

FIG. 7 is a circuit block diagram of another embodiment of the liquid crystal driving device of the present invention.

FIG. 8 is a circuit diagram of an example of a conventional liquid crystal drive device.

9 is a partial circuit diagram of the conventional common driver of FIG.

[Explanation of symbols]

 10 Liquid Crystal Driving Device 11 Power Supply Circuit 11a to 11d Voltage Dividing Selection Circuit 12 Voltage Dividing Circuit 13a to 13d Selection Circuit 14 Common Driver 14a to 14n Selection Circuit 15 Segment Driver 15a to 15m Selection Circuit R11 to R22 Voltage Dividing Resistance r1 to r8 Resistance In1 , In2 inverter NIn1, NIn2 non-inverter Tr1 to Tr6 transistors OP11 to OP14 operational amplifier V0 to V5 drive voltage

Claims (4)

[Claims] 1. A liquid crystal display panel in which liquid crystal is sealed between a pair of transparent substrates, and a plurality of scanning lines and signal lines are formed on the transparent substrate, and a plurality of types of driving by dividing a predetermined reference voltage into a plurality of voltages. A voltage generating means for generating and providing a voltage; a control signal generating means for generating a control signal for driving display data of the liquid crystal display panel and an alternating current driving signal for alternating current driving the liquid crystal display panel; A voltage for driving the liquid crystal display panel is selected from among the plurality of types of voltages provided by the voltage generating means, and a scan drive signal corresponding to the selected voltage is provided to a scan line of the liquid crystal display panel. The liquid crystal display panel receives a display drive signal selected from the plurality of types of voltages provided by the scanning signal generation means and the voltage generation means, and outputs a display drive signal corresponding to the selected voltage. Display signal generating means for providing the signal line to the signal line, the voltage generating means selects the predetermined voltage according to the AC drive signal to the scanning signal generating means and the display signal generating means, respectively. A liquid crystal driving device for providing the scanning signal generating means and the display signal generating means. 2. The voltage generating means includes a voltage dividing circuit that generates the plurality of types of voltages from the predetermined reference voltage, and a selection circuit that selects from the plurality of types of voltages. At least one power supply line of the plurality of power supply lines connected to the scanning signal generation means and the display signal generation means shares the selected plurality of voltages with the one power supply line based on the AC drive signal. 2. The liquid crystal driving device according to claim 1, wherein the predetermined voltage is provided to the scanning signal selecting means and the display signal generating means. 3. The scanning signal generating means selects, from a plurality of voltages selectively provided from the voltage generating means based on the control signal, for each scanning line, depending on whether the scanning timing of the scanning line is reached or not. A single and a predetermined voltage is selected, and a selection circuit that supplies the selected voltage to the scan line as a scan drive signal is provided, and the display signal generation unit generates the voltage based on the control signal. A single and predetermined voltage is selected from the plurality of voltages selectively provided by the means based on display data for each signal line, and the selected voltage is applied to the signal line to drive the display. 3. The liquid crystal drive device according to claim 1, further comprising a selection circuit provided as a signal. 4. The voltage generating means is configured to select, from the plurality of types of voltages provided by the voltage dividing circuit, a type that is less than the number of the plurality of types of provided voltages for each cycle of the AC drive signal. 4. The liquid crystal driving device according to claim 2, wherein a predetermined number of predetermined voltages are selected and the selected voltages are provided to each of the scanning signal generating means and the display signal generating means.